(* Copyright (C) 2010 School of Software Engineering, 
 * University of Science and Technology of China.
 *
 * This code is released under a BSD-style license.
 * See the file LICENSE for details.
 *)

signature LAYOUT =
sig
    type t

    val align: t list -> t
    val empty: unit -> t
    val indent: t * int -> t
    val print: t -> unit                     
    val seq: t list -> t 
    val str: string -> t  
    val toString: t -> string       
end
